Arc welding



My invention relates to are 'welding, parw ticuiarly to are weiding machines for automatically feeding he Vtezi weiding electrodes towaru and aw the woi'l; to strike and thereaitcr n'iaintain a "';fifeldi g En order to improve their w'cirrg eharacteristies as well as the quality the weld metal, welding electrodes are often coated 'with materials called fiuxes. Very often these eoatings are of consid ble thiclrness and electrically insulate the el ctrodes rendering them unsuited for use in automatic machines in which the welding current is to the ,surface of the electrode at a predeterrnined point as it is fed through the machine to the work. Heavy coated electrodes are generaliy' supplied in short iengths with one end thereof hared for inser= tion in a holder 'cy means of which current is fed to the eiectrode and the eleetrode fed to the worlr.

is an object of my invention to provide a welding machine for feeding heavily coated welding electrodes of eonsiderahle length into and out of engageinent with the work to strile and thereafter maintain an are and for supplying welding current to said electrodes as they are feol to the work.

It' is a further object of my invention to provide'means for removing a portion of the coating of coatecl electrodes and conducting weloing current thereto 'through the portion of the electrode thus exposed.

Further objects of my invention will become apparent from the following description taken in connection with the aceompanying drawing in which Fig. l is a partial view of an automatic are welding machine embodying one form of my invention' Fig. 2 a distorted perspeotive view illustrating the arrangement of parts of i, and Fig. 3 a diagrammatie illustration of the svlitching means employed in Figs. i and 2.

In Fig. 1 the welding head is mounted upon a carriage 1 supported on a track 2 along which it is propelled by a traversing motor 3 to p'erform a Welding operation on work which is held in the machine by a clamp a portion of which is shown at 5. The welding head comprises a feed motor 6 by means of which feed rolls 7 are rotated in the proper direction and at the proper speed to feed an electrode 8 from a reel 9 toward and from the work 4 to strike and thereafter maintain a welding are. In automatic machines the operation of the feed motor 6, or a transmission conneeting the feed motor With the feed rolls, is made to function in accordance with a charaeteristic of the Welding are to control the speed and direetion of electrode feed.

In the particular arrangement illustrated, the feed rolls 7 are provided with projections and wii. hereinafter he to as .sprocl'et whees "iVelding current is to the eiectrcde throu" i these projections which eng-age those ;oortiens the electrode from which the infsulating coating has been removed by suitable mears. mhe removing means may he a ieel, a saw, a miiling cutter, or the so inne; as it is adapted to remove a porI tion of the eoating from the electrode. In the particular instanee illustrated milling cutters 10 have been employed. These cutters mountecl on moi/able shafts 11 connected' to a motor 12 through flexihle couplings 13 and spur gears io. The bearings of shafts ll are mounted in swing'ing arms 15 pivoted at 16, the lower ends of which act as armatures and are drawn toward electrode 8 by magnets 17 when these magnets are energized. Arms 15 are normally biased outwardly by Springs 18 to a distance determined by the setting of serews air gaps between arms 15 and magnets i'l controlled by threaded cores Z which can ice adjusted to regulate the penetration. of the cutters intov the electrode 8. This adjustnient should he such that the ux is completely removed from the electrode which is held in proper position relative to the eutters by a guide In the arrangement illustrated the cutting means is periodically moved into engagement With the electrode by energizng magnets 17 through a switch 22 which is periodically closed to synchronize the operation of the -cutting means with the periodic engagement of the projections 23 of the sproeket Wheels 7 with the electrode, so that the portions exposed on the electrode by the Cutting means are in registry with the projections on the sprocket Wheels. In the particular instanee illustrated, the sprocket Wheels 7 are driven byithe motor 6 'through a shaft 24 provided with a gear 25 which meshes with gears attaehed to the sprocket Wheels 7. Two of the four gears and sprocket Wheels-employed in the machine illustrated are movably supported and are foreed into engagement with the fixed gears and the electrode by a spring' 26 attache'cl to the housings 27 in which they are mounted. Meshing with one of the fixed sprocket Wheels 7 is a gear wheel 28 on the shaft of which there is an adjustable cam 29. The cam 29 makes contact with a cam follower 30 attaehed to switch 22 and rotation of cam 29 periodically operates this switch. With the proper adjustment of cam 29 relative to gear 28 the number of teeth on this gear bears such a relationship to the number of teeth on the sprocket wheel gear With which it is meshing that switch 22 is operated at the proper time to advance the cutters 10 into engagement with the 'eleotrode to remove its coating at points separated from one another a distance equal to the pitch or distance between the electrode engaging portions of the projections 23 on the sprocket Wheels 'I and in registry therewith. The Welding electrode is held in proper position relative to the sprocket Wheels 7 by guides 31, 32 and 33 and fed to the work through a nozzle 34.

The apparatus above described is insulated from the welding carriage in order to prevent short circuit of the arc through the machine. It is not necessary to insulate the fiux removing means from the machine if the cutters are properly insulated. In some instances, it will not be necessary to insulate these cutters since they Will themselves be made of an insulating material. For example, it is not necessary to insulate certain types of grnding Wheels which are themselves made of an insulating material.

The operation of the apparatus above deseribed is as follows:-The electrode 8 is withdrawn from reel 9 by sprocket Wheels 7 and fed toward the work through nozzle 34. As it is fed past the cutting means 10, portions of this coating thereof are removed to bare the electrode so that current may be conducted thereto through projections 23 of the sprocket Wheels 7. The operation of the cutting means 10 is under the control of magnets 17 which are periodically energized from a source of supply 35 through a switch 22 which is under the control of cam 29, the arrangement being shown diagrammatically in Fig. 3. When the magnets 17 are energized the cutting means is forced into engagement with the electrode and when these magnets are deenergized the cutting means is moved to an inop'erative position through the agency of Springs 18. The energization of magnets 17 is synchronized with the rotation. of the sprocket Wheels 'Z to remove the flux coating from the electrode at points separate from one another a distance equal to the pitch of the projections 23 on the sprocket Wheels. This synchronization is obtained through the gearing above described and adiustment of the cam 29 relative to gear 28.

The particular embodiment above illustrated and described may be variously modified without departing from my invention. Other means may be provided for supplyng current to the bared portions of the electrode in place of the sprocket Wheels 7 and the means for supplying the current may be separate and distinct from the means employed for feeding the electrode toward and away from the Work. Likewise va-V riously modified flux removing means may be employed for exposing the electrode so that the current conducting means may come in contact therewith.

In the particular arrangement illustrated the mechanisms for removing the flux and for conducting welding current into the electrode are in the nature of attachments which can be associated With automatic arc weiding machines adapted for feeding bared electrode Wire in order to render them suitable for feeding heavily fiuxed electrode material. It is of course apparent that these means may form an integral part of the welding head and such modincations are contemplated.

whatlclaimasnewanddesiretosecure by Letters Patent of the United States, is:

1. Arc welding apparatus comprising means for feeding a coated electrode toward and away from the Work to strike and thereafter maintain a Welding arc, means for removing a part of the coating from said electrode and means for conducting welding current :into said electrode through the portion exposed by removing said coating.

2. Aro Weldng apparatus comprising means for feeding a coated electrode toward and away from the work to strike and thereafter maintain Aa welding arc, means for periodically removing a portion of said coating to expose said electrode, and means for conducting Welding current into said electrode through said exposed portions.

3. Arc welding apparatus comprising means provided with projections for engaging an electrode, and means for intermittently removing'V a portion of the coating from a fluxed electrode to expose it at points separated from one another a distance equal to the pitch of the projections on said electrode engaging means and in registry With said projections.

4. Arc welding apparatus provided with means having projections for periodically engaging a welding electrode, means for removing a portion of the coating from a fiuxed electrode to expose it at points separated from one another a distance equal to the pitch of the projections on said electrode engaging means and in registry with said projections, means for supplying current to said electrode through said electrode engaging means, and means for operating said electrode engaging means to feed the electrode toward and away from the work to strike and thereafter maintain a Welding arc.

5. Arc welding apparatus comprising means for removing a portionof the coatingfrom a coated welding electrode, means 'for periodically moving said coating removing means into engagement and out of engagement with a coated electrode, means provided with projections for engaging said electrode and conducting welding current thereto, means for synchronizing the operation of said means for moving the flux removing means into and out of engagement With said electrode to expose the electrode at points registering With the projections on said electrode engaging means, and means for operating said electrode engaging means to feed the electrode toward and away from the work to strike and thereafter maintain a Welding arc.

6. Arc welding apparatus comprising a cutter for removing a portion of the coating from a coated Welding electrode, means for Operating said cutter, means including an electromagnet for periodically moving said cutter into engagement with said electrode, a sprocket Wheel whose projections engage said electrode, switching means for controlling the energization of said electromagnet and for synchronizing the operation of said cutting means with the periodic engagement of the projections of said sprocket with said electrode to bare the electrode at 140 points in registry with the projections on said sprocket wheel, means for supplying current to said electrode through said sprocket wheel, and means for rotating said sprocket wheel to feed said'electrode toward and away from the work 145 to strike and thereafter maintain a Welding arc.

VERNI J. CHAPMAN. 

